It is well documented that persons can suffer negative consequences from exposure to certain analgesia and/or anesthetic gases; and particularly, nitrous oxide. The administration of nitrous oxide to patients is especially popular during dental procedures. The relatively short periods that the patient is exposed to the gas is generally accepted as being tolerable from a health perspective. A by-product of the administration of such gases, however, particularly during dental procedures in which the patient's mouth remains open and uncovered is a leakage of the administered gas into the care provider's breathing space from the patient's open mouth. Depending on the fit of the nasal mask against the patient's face, it is also possible for some leakage to occur thereabout while gas is administered.
The adverse health effects of exposure to low levels of nitrous oxide have been demonstrated in epidemiologic and laboratory studies. The effects range from those of the more bothersome type including irritability, headache, and nausea to the more severe including congenital abnormalities, spontaneous abortion, infertility, lymphoid malignancies, cervical cancer, and hepatic, renal and neurological disease.
In an effort to continue patient benefits from the administration of nitrous oxide, while minimizing, if not alleviating the negative effects upon the care providers, several air evacuation devices have been developed. One example is found in International Patent Application Number PCT/CA95/00504 in which a system entitled Ventilation of Medical Gases is described. The intake portions of this device, however, are positioned against each of the patient's cheeks in a space that the care provider may wish to occupy, or at least have clear during medical procedures, and especially dental procedures. Still further, the positioning of the intakes which are supported on, and substantially cover the patient's cheek areas can prove to be a disturbance to the patient.
Another attempted solution is found in International Patent Application Number PCT/SE89/00213 entitled Mouth Piece for Suction of Exhaled Air. This device is described as having wing members that are intended to be brought into the mouth of the patient and which rest upon the inner side of the mouth cavity. The facial and inner-mouth contact that this device requires also creates a disturbance for the patient which is desirably avoided.
Taking these exemplarily, but inadequate solutions into consideration, the need for improved and alternative methods has been recognized. Goals for such replacement options include patient comfort and effectiveness for minimizing care provider exposure to escape gas.